1. Field of the Invention
The present invention relates to a power supply system and, more particularly, to a system and method which enable customers to select different types of power suppliers.
2. Background Art
A related art system which pertains to supplying power to customers on the basis of the conditions desired by the customers is described in Japanese Laid-Open No. 78747/2000, which is entitled “POWER COMPANY SELECTING METHOD AND SELECTION SUPPORT SYSTEM”.
This related art pertains to the case in which different power companies have different charge systems, and enables a customer to select different contract conditions from each power company according to the conditions desired by the customer. It also presents a combination of the selected contract conditions to the customer.
However, this related art only provides customers with a selection method which merely takes the price of power into account. Electric energy is indispensable to the development of industries and human life, and in particular, the energy required to generate electricity is ideally generated from sources which are essentially inexhaustible and as friendly as possible to the environment.
Examples of such environmentally friendly energy are sunlight, wind power, small-scale water power using no dam, biomass (biological resources) such as wood chips, straw, excretions of livestock, geothermal heat transmitted from magma lying deeply beneath the earth's surface, waste heat utilization at factories or the like, and waste such as burnt refuse.
On the other hand, fossil fuels, such as petroleum, coal and natural gas, and uranium are exhaustible resources which will be completely consumed in the future. In addition, burning fossil fuels produce carbon dioxide (CO2) which seems to be the cause of global warming. Nuclear energy leaves radioactive wastes which are required to be treated with high reliability. Large-scale water power generation needs to build dams which are liable to destroy their surrounding ecological systems.
The primary source of the above-described biomass is wood. Burning wood produces CO2, but living wood absorbs CO2 during photosynthesis. If trees are planted in place of burnt trees so as to maintain the area of a forest, it is possible to maintain the proportion of CO2 in the atmosphere. Accordingly, wood is a so-called green power generation energy which does not cause the problems of global environmental loads and the exhaustion of resources.
As described above, even the case of generating the same amount of power greatly differs in its influence on the environment and in the extent of exhaustion of global resources according to the kind of energy required for the power generation.
Customers have heretofore been unable to know the extent of the influences of powers supplied to the customers on global environmental loads, i.e., the amount of emission of CO2 which is based on the difference between the kinds of energy sources required for power generation, as well as the extent of exhaustion of energy sources. In other words, customers' attempts at reducing global environmental loads have so far been limited to only the method of reducing electric power usage through energy saving, and customers have had few specific choices as to how they can actually promote the conservation of the beautiful earth.